Rafter Radiocarbon Laboratory, GNS Science, Lower Hutt 5010, New Zealand.
CIRES, University of Colorado at Boulder, Boulder, Colorado 80309, United States.
Environ Sci Technol. 2022 Jul 19;56(14):9882-9890. doi: 10.1021/acs.est.1c07994. Epub 2022 Jun 27.
COVID-19 lockdowns resulted in dramatic changes to fossil fuel CO emissions around the world, most prominently in the transportation sector. Yet travel restrictions also hampered observational data collection, making it difficult to evaluate emission changes as they occurred. To overcome this, we used a novel citizen science campaign to detect emission changes during lockdown and engage youth in climate science. Citizen scientists collected grass samples from their garden or local park, from which we analyzed the radiocarbon content to infer the recently added atmospheric fossil fuel CO mole fraction at each sampling location. The local fossil fuel CO mole fractions during lockdown were compared with a "normal" nonlockdown period. Our results from 17 sites in five cities around New Zealand demonstrate dramatic reductions in traffic emissions of 75 ± 3% during the most severe lockdown restriction period. This is consistent with sparse local traffic count information and a much larger decrease in traffic emissions than reported in global aggregate estimates of emission changes. Our results demonstrate that despite nationally consistent rules on travel during lockdown, emission changes varied by location, with inner-city sites typically dominated by bus traffic showing smaller decreases in emissions than elsewhere.
COVID-19 封锁措施导致全球范围内的化石燃料 CO 排放发生了显著变化，交通部门最为明显。然而，旅行限制也阻碍了观测数据的收集，使得难以在排放发生时评估其变化。为了克服这一困难，我们利用一项新的公民科学运动来检测封锁期间的排放变化，并让年轻人参与气候科学。公民科学家从他们的花园或当地公园采集草样，我们从中分析放射性碳含量，以推断每个采样地点最近添加的大气化石燃料 CO 分数。将封锁期间的当地化石燃料 CO 分数与“正常”非封锁期进行比较。我们在新西兰五个城市的 17 个地点的结果表明，在最严格的封锁限制期间，交通排放量急剧减少了 75±3%。这与稀疏的当地交通计数信息一致，并且与全球排放变化综合估计报告的交通排放量减少幅度相比，降幅更大。我们的结果表明，尽管在封锁期间全国范围内都有一致的旅行规定，但排放变化因地点而异，市中心站点通常以公共汽车交通为主，其排放量减少幅度小于其他地方。
