"What does a garden have to do with the chemistry of the atmosphere and air quality?" 

Good question posed by NASA's Goddard Space Flight Center Web site. And, in regards to the two-month plan started yesterday in China to remove half of the capital's 3.3 million per capita cars from city streets on alternate days, I thought it might be nice to check out how we humans contribute to the quality (or lack thereof) of air. 

NASA is flying an Aura satellite, which is studying atmospheric chemistry and air pollution from space "by seeing how ozone in the air damages the leaves of certain plants. Ozone is formed when chemical pollutants that are by-products of human activities such as biomass burning and the combustion of fossil fuels react in the presence of sunlight." 

Different plants are more sensitive to ozone than others, like the white dogwood and cardinal flower. According to NASA's site, and based on research culled from the Great Smokey Mountain National Park and elsewhere, "when exposed to high concentrations of ozone over time, such plants develop characteristic tiny, evenly spaced dots known as 'stippling' and also yellowing on the upper surfaces of their leaves. Eventually leaves that accumulate enough ozone damage die and fall off." 

And those plants that are performing photosynthesis and cleaning out the environment for us humans are cycling the same atmosphere through their cells as we are. So kudos to Beijing, China for taking a step in the right direction, whether their reasoning centers around clearing out the skies of pollution or reducing the number of cars on the road. Any little bit of effort to safeguard the environment adds up to a meaningful movement; I'd like to see another great world superpower, the US, make similar strides in the battle for Mother Nature. 

• What do you think?