rabbit during peak haze (PSI 200+) in Singapore

updated 14 May 2026 by xavier fok

Singapore’s haze season runs roughly from August to October, when Sumatran agricultural fires push smoke across the Strait of Malacca and PM2.5 levels climb through the NEA’s PSI bands. most years the PSI sits in the uncomfortable but manageable Unhealthy range (101-200) for a few days and then clears. but in bad years — 2015 being the worst recorded — PSI readings breach 200, 250, even 300, and the air outside takes on a yellowish tint you can smell from your living room.

for human adults this is genuinely bad. for rabbits it is a different category of crisis. rabbits breathe three to five times faster than we do, their respiratory systems are anatomically far more delicate, and they cannot cough out irritants the way we can. if you own a rabbit and live in SG, understanding the PSI scale and having a tested indoor air protocol before haze season arrives is not optional — it is part of responsible ownership.

the PSI scale — what 100, 200, 300 actually mean for rabbits

the NEA 24-hour PSI scale breaks into five bands:

under 50, Good — normal outdoor activity for everyone, including rabbits on balconies.
51-100 Moderate — sensitive humans should reduce prolonged outdoor exertion. for rabbits, balcony time should already be capped and monitored.
101-200 Unhealthy — the NEA advises the general population to reduce outdoor activity. for rabbits, balcony access should stop entirely. windows facing the prevailing wind direction should be kept shut.
201-300 Very Unhealthy — this is the threshold where your indoor air management protocol needs to be fully activated, not just started. HEPA filters should be running, AC on recirculate, and window sealing in place.
301+ Hazardous — peak haze. outdoor air is dangerous even for brief exposures. every gap in your home’s envelope — door frames, bathroom exhaust vents, air gaps around service ducts — becomes a vector for PM2.5 infiltration.

the critical number to understand is respiratory rate. a healthy adult human breathes 12-20 times per minute at rest. a healthy rabbit breathes 30-60 times per minute at rest. at PSI 250, with PM2.5 concentrations running at roughly 150 micrograms per cubic metre, your rabbit’s lungs are being exposed to two to four times more particle load per minute than yours. the damage accumulates faster, and the physiological reserve to absorb it is smaller.

the SG haze cause

Singapore does not produce its own haze. the smoke originates from land-clearing fires in Sumatra and, in worse years, Kalimantan, where farmers and plantation companies burn peat and secondary forest during the dry season to clear land cheaply. peat fires in particular burn deep and hot, producing fine particulate matter that travels hundreds of kilometres at altitude.

the Southwest Monsoon (June to September) drives these smoke plumes directly toward SG. when the monsoon weakens or stalls in August-October, smoke concentrations peak. the NEA publishes 1-hour and 24-hour PSI readings at haze.gov.sg and the myENV app, and 24-hour PSI is the standard metric for health guidance — but 1-hour readings give you real-time trend data that is worth watching when readings are climbing fast.

understanding the cause matters for one practical reason: haze events are not brief. a regional fire season can sustain elevated PSI for 10-20 consecutive days. you are not managing a single bad afternoon; you are managing a multi-week indoor confinement period for your rabbit.

the rabbit respiratory risk profile

rabbits are obligate nasal breathers. they cannot breathe through their mouths as a default — mouth breathing in a rabbit is a clinical emergency sign, not an adaptation. all air entering the lungs passes through a nasal passage that, relative to body size, is much shorter and less filtration-efficient than a human’s upper airway.

their lungs are small relative to body mass, and their pleural cavity (the space around the lungs) is proportionally tiny. this limits how much the lungs can expand under distress. in humans, respiratory distress triggers a compensatory increase in breathing depth and rate that can be sustained for hours. in rabbits, the compensatory headroom runs out quickly. a rabbit in respiratory distress can decompensate — go from stressed breathing to near-respiratory failure — in under an hour.

there is also no cough reflex. humans clear PM2.5 particles from airways through coughing. rabbits cannot cough. particles that reach the bronchioles stay there, triggering inflammation, mucus accumulation, and — with repeated exposure over days — chronic bronchial damage.

finally, rabbits are prey animals that suppress signs of illness as long as possible. by the time you notice respiratory distress in a rabbit, the problem is already well-established. this is why monitoring for early signs during any PSI-200+ event is non-negotiable, even when your rabbit appears to be behaving normally.

the early warning signs in your rabbit

learn to distinguish normal from abnormal before haze season arrives. the signs of haze-induced respiratory distress in rabbits follow a rough progression:

early signs (act now, do not wait):

respiratory rate above 60 per minute at rest. count breaths for 30 seconds and double it. if you count more than 30 in 30 seconds, that is above 60/min.
nostril flaring. the nostrils should open and close gently. active flaring means the rabbit is working to pull in more air.
subtle lethargy — the rabbit is less interested in hopping around, sits in a loaf position longer than usual, or is slower to come to you.
slightly watery eyes. PM2.5 is an irritant and the eyes respond before the lungs show overt signs.

intermediate signs (contact your vet today):

visible ribcage movement. you should not normally see the chest wall moving with each breath. when you can, breathing effort has increased significantly.
hunched posture. the rabbit curls inward with elbows splayed, which opens the chest cavity — this is a compensation posture for impaired breathing.
nasal discharge, clear or cloudy. the nasal passages are producing excess mucus to trap particles.
reduced appetite. a rabbit that is struggling to breathe will not eat normally. reduced cecotrope consumption (the soft night droppings they re-ingest) is an early food-intake signal that owners often miss.

severe signs (emergency vet visit immediately):

mouth breathing or open-mouth breathing of any kind.
blue-tinged gums or tongue (cyanosis) — though this is very late-stage and means oxygen saturation is critically low.
complete food refusal combined with laboured breathing.
inability to hold an upright posture.

if you are seeing early or intermediate signs during a PSI 200+ event, do not adopt a wait-and-see posture. rabbits deteriorate faster than dogs or cats under respiratory stress. see rabbit respiratory issues in Singapore for a deeper breakdown of the clinical picture.

the indoor air management protocol

when PSI crosses 200, activate the following in full. not partially — in full.

HEPA filter placement. position the HEPA unit within one metre of your rabbit’s cage or pen. HEPA filters are rated by CADR (Clean Air Delivery Rate), expressed in cubic metres per hour or cubic feet per minute. placement matters because HEPA units clean air in a cone — the further the cage is from the unit, the more unfiltered ambient air dilutes the output. brands available at FairPrice, Shopee, and Courts include Xiaomi Mi Air, Philips, Sharp, and Honeywell. all of these have units with CADR ratings suitable for HDB bedrooms and living rooms. run the HEPA on its highest effective setting — not max fan speed (too noisy and disruptive for the rabbit) but the highest speed that does not visibly stress the animal.

AC on recirculate mode. standard AC in SG homes pulls a small percentage of outdoor air through a fresh-air intake. during haze, this is a direct PM2.5 feed into your home. switch your air conditioning unit to full recirculate (or “fan only” in recirculate mode, if you are trying to avoid overcooling). check your unit’s manual if you are unsure — many Daikin, Mitsubishi, and Panasonic split units in SG have a recirculate setting that closes the outdoor air damper. if your unit does not have this, set it to cooling mode and seal the fresh air intake manually (a strip of tape over the external intake grille on the outdoor unit will not damage the unit).

window and door sealing. windows should be fully closed. use rolled-up towels along the bottom of doors that open to hallways or balconies. if your HDB has a service yard with louver windows that cannot fully close, place a sheet of cardboard or thick fabric against the louvers. weatherstripping kits are available at hardware stores (ACE Hardware at Jurong Point, FairPrice Xtra) and take less than 30 minutes to apply to a window frame. this is a worthwhile permanent installation for any SG home with a rabbit.

bathroom exhaust fans off. bathroom exhaust fans vent directly to the outside and, when running, create negative pressure that pulls outdoor air into the home through gaps. switch them off during peak haze and ventilate bathrooms by opening the internal bathroom door instead.

the HEPA filter math

this section matters if you are buying a new unit or checking whether your existing unit is adequate.

the formula is: room volume ÷ CADR rating = air change time in hours.

multiply your room’s floor area (square metres) by ceiling height (typically 2.6m in SG HDB flats) to get volume. divide by the HEPA unit’s CADR rating in m³/h. the result tells you how long it takes to process the entire room’s air volume once.

example: a 10m² bedroom with 2.6m ceilings = 26m³. a Xiaomi Mi Air Purifier 4 Pro has a CADR of ~500 m³/h. 26 ÷ 500 = 0.052 hours, or about 3 minutes per air change. that is well-suited for a bedroom.

for a 20m² living room (52m³), that same unit takes about 6 minutes per air change — still effective. a unit with CADR of 200 m³/h in the same 52m³ room takes 16 minutes per air change, which means particles linger longer. during PSI 200+, aim for air change times under 10 minutes in the room where your rabbit lives.

one more thing: HEPA filters need replacement or cleaning on schedule. a clogged filter runs the fan but moves little air and provides poor filtration. check the filter indicator light and do not ignore it during haze season. if you have not changed the HEPA cartridge in over a year, replace it now.

the AC vs no-AC household strategy

some rabbit owners keep their homes without AC — either by choice, or because the unit is broken, or because they live in a space without ceiling coverage. during PSI 200+ events, this creates a harder problem.

with AC and recirculate available: this is the preferred setup. run AC to keep the room temperature below 28°C (rabbits are vulnerable to heat stroke above 28°C as well — see heat stroke prevention), use recirculate mode, and run the HEPA unit alongside it. the combination handles both thermal and particulate risks simultaneously.

without AC: you are managing a trade-off between heat and air quality. the options in order of preference:

close all windows, run HEPA on high, accept that the room will be warmer and manage thermal risk with fans (fans do not bring in outside air, they circulate existing indoor air). place a ceramic tile or cool damp towel near the cage for the rabbit to press against.
if the room becomes dangerously hot (above 30°C), crack one window on the side of the apartment least exposed to the prevailing wind, and place the HEPA unit directly in front of that window gap to filter incoming air. this is imperfect but better than heat stroke.
do not use a portable evaporative cooler (swamp cooler) as it works by drawing in outside air and may increase particulate infiltration.

for HDB households without AC, peak haze periods are also a reason to have a battery-powered portable AC unit on standby, or to arrange temporary relocation of the rabbit to a friend’s air-conditioned home.

the multi-day haze prep

when PSI forecasts suggest 3 or more days above 200, treat it like a supply preparation exercise:

hay storage. hay is the bulk of a rabbit’s diet and must be kept dry. during haze, if you are ordering hay and the delivery window falls on a peak haze day, haze particles can settle on fresh hay left outside a building. receive deliveries indoors directly, and store hay in a sealed container (a large zip-lock bag or an airtight plastic bin). ensure you have at least 7 days of hay on hand when a haze event is forecast.

fresh vegetables. leafy greens accumulate surface PM2.5 quickly if they have been exposed outdoors at the market or during transport. wash all vegetables thoroughly before feeding during haze periods. if possible, source vegetables that have been stored indoors (supermarket rather than wet market stall) during peak haze.

water. rabbits need clean water. tap water in SG is safe and unaffected by haze, so this is less of a concern — but ensure the water bowl or bottle is covered when not in use to prevent particulate settling on the water surface.

your own supplies. multi-day haze events are when you may also need to avoid going out frequently. stock up on hay, pellets, and fresh greens at the start of the event so you minimise outdoor exposure for yourself as well.

indoor enrichment substitutes

during multi-day haze events, your rabbit cannot go on the balcony, cannot be let out into areas that are less well-sealed, and should have their activity managed indoors. this creates a boredom and frustration risk — especially for high-energy breeds like Lionheads and Holland Lops.

substitute enrichment that works in a confined indoor space:

cardboard boxes and tunnels. a large cardboard appliance box with entry and exit holes cut into it becomes a tunnel and hideout simultaneously. rabbits shred cardboard safely and this activity absorbs significant time. see best rabbit toys and enrichment in Singapore for a full list of safe materials.

snuffle mats. a commercially available snuffle mat (a mat with rubber fingers into which you push small pieces of hay or pellets) activates foraging behaviour without requiring floor space. these are available on Shopee for SGD 15-30.

scatter feeding. instead of placing hay in a hay rack, scatter a portion of it across a clean area of the pen floor. the rabbit has to nose through and find it, which mimics natural foraging and extends feeding time from minutes to an extended session.

foraging puzzles. cardboard tubes stuffed with hay and folded closed at both ends, or a small stack of paper cups with hay inside, give the rabbit a physical problem to solve. rotate these daily so novelty is maintained.

training sessions. short, low-exertion clicker training sessions — teaching a rabbit to touch a target stick, for instance — provide mental engagement without physical output. 3-5 minute sessions twice a day work well.

bonding time. supervised floor time in the most well-sealed room in the house (usually a bedroom with AC running) allows the rabbit to explore, stretch, and interact with you. keep these sessions in the filtered air zone.

the bonded pair / multi-rabbit factor

if you have two or more rabbits housed together or in adjacent pens, the respiratory risk compounds:

more animals in a space means higher CO2 output and higher oxygen demand from the shared air volume. in a well-ventilated space this is irrelevant, but in a sealed-up haze shelter with recirculated AC, it matters. ensure your HEPA unit’s CADR is adequate for the full room volume, not just the single-rabbit space.

bonded pairs also groom each other, and PM2.5 that settles on fur gets ingested during grooming. during peak haze, increase grooming sessions yourself — gently brush both rabbits daily to remove surface particulate before they ingest it through self-grooming.

multi-rabbit households should watch all animals for early warning signs simultaneously. if one rabbit is showing signs of respiratory stress, assume all co-housed rabbits are under similar particulate stress even if they are not yet symptomatic.

the vet response

if your rabbit shows intermediate or severe respiratory signs during a haze event, the standard vet pathway in SG is:

respiratory consult. expect SGD 150-300 for an emergency or after-hours exotic vet consultation. not all general vets in SG are competent to treat rabbit respiratory conditions — ask specifically about exotic animal or rabbit experience when you call. see vets in Singapore for a curated list of rabbit-competent practices.

chest X-ray. an X-ray will show whether there is consolidation (fluid or mucus in the lung fields), which is the most serious haze-induced outcome. X-rays cost approximately SGD 80-150 and provide the vet with the information needed to distinguish haze-related bronchial irritation from pneumonia, which requires antibiotic treatment.

supplemental oxygen. if the rabbit is showing visible respiratory distress, oxygen therapy at the clinic will stabilise breathing. this costs approximately SGD 100-300 per day depending on delivery method and clinic. do not resist this recommendation — oxygen therapy in the first hours of respiratory decompensation dramatically improves outcomes.

nebuliser therapy. a nebuliser converts saline or medication into a fine mist the rabbit inhales in a small chamber. clinics offer in-clinic nebulisation, and some owners purchase home nebuliser units (SGD 200-500) for rabbits with known chronic respiratory conditions. the vet may prescribe bronchodilators or mucolytics for nebuliser use at home. if your rabbit has previously had respiratory issues (including snuffles/Pasteurella), discuss owning a home nebuliser with your vet before haze season.

corticosteroids. for airway inflammation, a short course of corticosteroids may be prescribed. these reduce bronchial swelling quickly but suppress immune response, so the vet will balance this against infection risk. follow the prescribed course exactly.

post-haze cleanup

when the PSI drops below 100 and stabilises there for 24+ hours, it is tempting to throw open all the windows and consider the crisis over. take a phased approach instead:

HEPA filter check. the HEPA cartridge will have captured a significant quantity of PM2.5 during the event. check the filter — it may be visibly grey or dark. if it is heavily loaded, replace it before resuming normal use. a clogged filter is ineffective and in some units triggers a bypass that recirculates unfiltered air.

surface wipe-down. PM2.5 that entered the home before you fully sealed it will have settled on surfaces — shelves, the cage wire, the pen floor, soft furnishings. wipe hard surfaces with a damp cloth. wash any fabric items the rabbit has contact with (blankets, pen liners) before resuming use.

cage and pen scrub. give the cage a full wipe-down with a rabbit-safe cleaner (diluted white vinegar works and leaves no harmful residue). replace hay and discard any hay that was stored open during the haze event.

ventilation flush. once PSI is comfortably below 100, open all windows for 2-3 hours to flush the indoor air and remove any CO2 buildup from the extended sealed period. do this when you can supervise — a post-haze wind shift can briefly spike PSI again.

rabbit observation period. maintain close respiratory monitoring for 48-72 hours post-haze. some rabbits develop delayed inflammatory responses as their airways react to particle accumulation. if early signs appear during the post-haze window, treat them with the same urgency as during the event itself.

the long-term respiratory consequences

a single PSI 200+ haze event, managed well with indoor air protocols, is unlikely to cause permanent respiratory damage in an otherwise healthy rabbit. the risk of lasting damage rises significantly with:

repeated annual exposure over multiple haze seasons without air management.
haze events that last 10+ days, especially if the household does not have AC or adequate HEPA coverage.
rabbits that already have underlying respiratory conditions such as Pasteurella infection (snuffles), dental disease affecting nasal passages, or anatomical issues common in flat-faced breeds like Lionheads.

long-term PM2.5 exposure in rabbits can cause chronic bronchitis, fibrotic lung changes, and increased susceptibility to bacterial respiratory infections. these are not reversible. the investment in a good HEPA unit and an AC unit you understand how to switch to recirculate mode is direct prevention of a long-term health cost.

if your rabbit has had two or more haze-related respiratory episodes, discuss a baseline chest X-ray with your vet outside of haze season to establish a reference image. having that baseline makes it easier to detect progression if another episode occurs.

what owners often get wrong

“I will close the windows when PSI hits 200.” PM2.5 penetrates through standard window seals at concentrations meaningful to rabbits well before PSI 200. at PSI 150, indoor PM2.5 in an unsealed HDB flat is already elevated. begin window sealing at PSI 150, not 200.
“The AC is on, so the air is filtered.” standard residential split AC units in SG do not filter PM2.5. they cool air but the filtration is a coarse pre-filter for dust, not fine particulate. HEPA is a separate device and non-negotiable during peak haze.
“My rabbit is eating normally, so she is fine.” early respiratory distress does not immediately suppress appetite. by the time a rabbit stops eating, respiratory compromise is already intermediate or severe. watch breathing rate, not food intake, as your primary indicator.
“The haze always clears in a day or two.” some haze events — notably the 2015 Sumatran fire season — sustained PSI above 100 for nearly three weeks. do not plan around a 48-hour window. treat the first forecast of PSI 200+ as the start of a potential 2-week indoor management period.
“The HEPA is running, so I don’t need to seal the windows.” a HEPA unit in a room with open or poorly sealed windows is fighting a constant influx of contaminated outside air. it can never win that race. sealing is a prerequisite for HEPA to be effective, not an optional addition.

rabbit respiratory issues in Singapore — the clinical picture, from snuffles to pneumonia
general haze care for rabbits in Singapore — the broader haze season guide covering PSI below 200
best rabbit toys and enrichment in Singapore — foraging puzzles, snuffle mats, and safe chew options for indoor confinement
storm and power outage rabbit prep — multi-day emergency planning framework that applies equally well to haze events

this article is for informational purposes only and does not substitute veterinary advice. if your rabbit is showing any signs of respiratory distress, contact a rabbit-competent vet in Singapore immediately. PSI readings referenced are based on the NEA 24-hour PSI scale. vet cost estimates are approximate as of 2026 and may vary by clinic and case complexity.