相对湿度： the relative humidity
灰霾： dust (灰尘) haze
空气质量指数：air quality index
PM的全称： particular matter (微粒物)
机动车燃油： burning of fossil fuels in vehicles.
发电厂： power plants
工业生产： industry processes.
防毒口罩： anti-dust masks
空气净化器： air purifies
雾霾：fog and haze
outdoor barbecues 户外烧烤
e.g. Beijing has imposed a ban on outdoor barbecues in order to improve the air quality. I don't get(理解) why they did that. I really enjoyed hanging out with friends at night and had some kebabs(烤串儿) outdoors.
make strenuous efforts to clean up the air 努力净化空气
e.g. What I loathe(憎恶) the most in Beijing is the air pollution. The government has been making strenuous efforts to clean up the air, but it seems like there has been no progress.
smog, haze 雾霾
e.g. We suffer from terrible smog from time to time, which is quite damaging to our health. I believe the haze will force me to move to another city.
urban area 城区 suburban areas 郊区
e.g. The problem with the urban area is that it's usually quite congested(拥堵的) during peak hours(在高峰期). Wait, no, actually, it's more or less the same in suburban areas now.