We will have a pretty chilly weekend, but it will get even chillier a couple of days into next week. A tough of low pressure will sit just to our west over the weekend, sending occasional impulses toward us, but it’s not likely they will bring us any showers before late Sunday. High temperatures on Saturday and Sunday will stop in the low 60s, with some of the outlying valleys and cold microclimates seeing some morning frosts. Scattered showers through Monday will come before the trough passes over us, after which rain and snow becomes likely Tuesday and Wednesday, with high temperatures dropping to the 50s. There could be enough instability during that event to spring up some thunderstorms as well. Conditions clear up, dry up and warm up back into the 70s by the end of the work week.

Yesterday, we talked about how particulate pollution is most problematic in the winter. The situation is much different in the summer, and that’s when another kind of pollution becomes an issue: ozone. While ozone is a good thing to have in our stratosphere (it blocks dangerous UV radiation), it is an irritant to breathing down here at the surface.

Ground level ozone forms primarily from reactions between two major pollutants: Volatile Organic Compounds (VOC) and Nitrogen Oxides (NOx). VOCs come from gasoline pumps, chemical plants, and auto-body shops among other sources. NOx is emitted from cars, power and industrial plants. Sunlight is needed to stimulate the reactions between these compounds, and therefore it is more prevalent in the summer months when there’s more sunshine.

Obviously, we’ve all got to breathe, and every time we do, we are exposed to whatever gunk is in the air. Most can handle a certain level of pollution, but when you exercise, work in the yard or do any other strenuous activity, you are pulling in a lot more air and the effects of pollution can be more critical. That’s especially true for those with lung disease, the very young or very old, and those with heart concerns. If you fall into any of those categories, make use of the Air Quality Index (AQI) to help you plan your activities. More on that next time.