Smog settles over Lahore and other Punjab cities for long stretches in the cooler months. Much of the health risk comes from fine particles too small to see, and most of the precautions below come down to breathing fewer of them.
What the particles do
The finest particles in smog are called PM2.5. They are small enough to travel deep into the lungs, and some can pass into the bloodstream.
Breathing them can irritate your airways and bring on coughing or difficulty breathing, and they can make asthma worse. In people with heart disease, particle pollution has been linked to heart attacks and an irregular heartbeat.
Who needs to be more careful
Children, older adults, pregnant women and anyone with heart or lung disease are at greater risk. So are people who spend long hours outdoors for work, such as traffic police and rickshaw drivers.
If you have asthma, follow your asthma plan and keep your inhalers within reach. Before the season starts, ask your doctor what to change if your breathing gets worse, and keep a few days' supply of your regular medicines at home.
Reading the AQI
Air quality apps show an Air Quality Index, or AQI, and a higher number means dirtier air. On the US scale, which many apps display, readings up to 50 are good and 51 to 100 are moderate. The air is unhealthy for sensitive groups at 101 to 150, unhealthy at 151 to 200 and very unhealthy at 201 to 300. Anything above 300 is hazardous.
Readings change during the day. On a bad day, save the evening walk or the cricket match for whenever the number is lowest, and skip running or other hard exercise outdoors, since breathing hard pulls more particles into your lungs.
Masks that filter smog
A dust mask, or a scarf or bandana tied over the face, will not protect you from these particles. An N95 respirator can, provided it fits snugly with no gaps at the edges.
Check for gaps around your nose and cheeks each time you put one on. Air that leaks past the edges has not been filtered.
Children under two should not wear a respirator. Adults with heart or lung disease should ask their doctor before wearing one.
Cleaner air indoors
Pick one room, usually the one you sleep in, and keep its doors and windows shut on the worst days. A portable air cleaner in that room will bring the particle level down. Change its filter as often as the maker recommends.
Avoid making smoke of your own indoors: no cigarettes, candles or incense (agarbatti), and no long frying sessions while the air outside is bad. Gas heaters add pollution too.
In the car, close the windows and switch the air conditioning to recirculate.
When to see a doctor
Feeling unwell on smoggy days is a reason to call your doctor, especially if a cough or wheeze will not settle, your chest feels tight, or you need your reliever inhaler more than usual.
Chest pain, severe breathlessness, blue lips or confusion need emergency care. Go to a hospital and do not wait to see if it passes.
