Trees can increase air pollution - use air convection

http://newatlas.com/trees-increase-smog-ozone-heat-wave/49607/?utm_source=Gizmag+Subscribers&utm_campaign=090be4bd72-UA-2235360-4&utm_medium=email&utm_term=0_65b67362bd-090be4bd72-92792417
 says:
"A recent study by a Berlin-based team of scientists has revealed that during heat waves, trees in a city can actually contribute to higher levels of air pollution." When plants are hot they can release more volatile organic compounds and this reacts with nitrogen oxides to form ozone. Ozone is a major pollution hazard. One can reduce nitrogen oxides by having electric cars. See later in this blog for converting ammonia to hydrogen for fuel cells for electric cars. Again solar air heaters can increase convection of air and dilute pollution. On how to build your own solar air heater, see http://www.builditsolar.com/Experimental/PopCanVsScreen/PopCanVsScreen.htm