Surviving summer's noxious brew

As summer starts to sizzle, the air quality also suffers. And in places such as Beijing, the combination of smog, dust particles, sand and heat all add up to what could seem to be a noxious brew. On occasion, with a little focus, you could actually taste the air.

Dr Brent Powis, the World Health Organization's Beijing environmental consultant, says the hot air fuels "the cocktail chemical mix" that is common during warmer days devoid of wind or rain.

"It is worse in the summer," Powis says. "The increasing temperatures can actually increase the levels of ozone in the atmosphere, which can have significant health effects."