Air quality monitoring 2015 annual report: Sequoia and Kings Canyon National Parks

Meyer, Erik; Esperanza, Annie

Sequoia and Kings Canyon National Parks (SEKI) periodically experience the worst air quality in the National Park Service. Elevated ground-level ozone (O3) may be the most damaging pollutant in SEKI, when in summer months, concentrations often exceed the federal ozone health standards of 75 parts per billion (ppb) averaged over an 8 hour (h) period. Ozone is a secondary pollutant, formed when nitrogen dioxide (NOx) and volatile organic compounds (VOCs) combine with warming temperatures and sunlight. Above 75 ppb, ozone may have negative health effects particularly for sensitive groups, such as children, older people, and those with heart or lung disease (Table 1). As O3 increases, others beyond sensitive groups may be affected (EPA 2015). Examples of ozone health effects include chest pain, coughing, throat irritation, congestion, and exasperation of bronchitis, emphysema, and asthma. The harmful effects of increased O3 go beyond human health and into park ecosystems, including widespread damage to sensitive vegetation, which could alter how plants grow, and produce and store food. From early June to late October 2015, O3 conditions were monitored and forecasted to employees and the public from two locations in SEKI: the Ash Mountain air quality station located in the foothills and the Lower Kaweah air quality station in the Giant Forest (Figure 1). Daily ozone AQI levels were forecasted through an internet-linked automated process that summarizes ozone and meteorology data from each station from the prior day, as well as expected conditions from weather forecasts. The forecasts are then made available through Twitter Inc. (@SequoiaKingsAir) and embedded for greater outreach through the SEKI Air Advisory website (NPS 2015b). At the end of each advisory season, validated data is downloaded from NPS Gaseous Pollutant and Meteorological Data Access Page, and graphics are generated using the OpenAir package in R Statistical Software (Carslaw and Ropkins 2012, R Software 2015). For all of 2015, the Ash Mountain site measured 53 days exceeding federal health standards (Figure 1). This was the most of any NPS unit, and was followed by the Lower Kaweah station in SEKI (23 days) and the Black Rock station in Joshua Tree N.P. (23 days). Most other NPS O3 stations measured 1 to 8 days or less exceeding federal health standards (NPS 2015a). Although air quality remained poor in SEKI compared to other NPS sites, Ash Mountain and Lower Kaweah recorded the first and third fewest federal health exceedances since 2000, respectively, and didn’t reach Unhealthy AQI levels the entire summer (Figure 2). During the advisory season (June through October) in Ash Mountain, August had the highest number of days at the Unhealthy for Sensitive Groups level (Figure 3, Figure 4), as well as the most hours exceeding health standards (Figure 5). During this period, 297 hours (h) over 48 days exceeded 75 ppb, which was down compared to a similar time frame in 2014 (321 h over 53 days). At Lower Kaweah during the advisory season, June had the highest number of days at the Unhealthy for Sensitive Groups level (Figure 6, Figure 7), as well as the most hours exceeding health standards (Figure 8). For the monitoring season, 132 h over 21 days exceeded 75 ppb, which was down compared to the same time frame in 2014 (184 h over 31 days) and 2013 (226 h over 37 days). For a more extensive look at air quality conditions in 2015, including particulate matter pollution, please refer to figures 9 through 16 at the end of this report.

Air quality monitoring 2015 annual report: Sequoia and Kings Canyon National Parks

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