Coexistence field trials between MON810 and conventional maize in Mallorca as a basis for a regional regulatory proposal based on scientific evidence in the times of genome editing.

This paper reports the first coexistence field trials between transgenic and conventional maize carried out under Mediterranean island conditions. Their purpose was to assess the local validity of pollen barriers and sowing delays as coexistence strategies as a basis for a regional regulation on the subject. Two field trials were performed in two agricultural states of Alcudia and Palma, in Mallorca (Spain). In the first one, two adjacent plots were synchronously sown with conventional and transgenic maize, respectively. In the second trial, the previous design was replicated, and two additional plots sown with GM maize were added, paired with their respective conventional recipient plots sown 2 and 4 weeks later. All conventional plots were located downwind from their respective GM plots. Of the two conventional plots in sowing synchrony, only one of them required a 2.25 m pollen barrier to meet the 0.9% labeling threshold. A 4-week sowing delay between GM and non-GM plots proved to be enough to keep the GM content of the recipient plots below the legal threshold. However, with a 2-week sowing delay additional coexistence measures such as pollen barriers might be needed, as suggested in the literature. Results are consistent with previous research conducted in the northeast of Spain, thus validating in the island's agroclimatic conditions a model successfully tested in that peninsular region which allows to accurately estimate the need and width of pollen barriers. The results presented here could perhaps be extrapolated to other islands, coastal areas, and regions with stable prevailing winds during the maize flowering season.

Diurnal variations in primary and secondary organic aerosols in an eastern China coastal city: The impact of land-sea breezes.

The land-sea breeze circulation significantly impacts the atmospheric transport of organic aerosols in coastal regions. However, the links between organic aerosols and land-sea breezes remain poorly understood. In this study, organic marker compounds for biomass burning, primary biological aerosols, biogenic and anthropogenic secondary organic aerosols (SOA) in fine particles from a coastal city in East China were analysed using gas chromatography-mass spectrometry. Land-sea breeze circulations were identified to explore their potential influence on organic molecular compositions. Organic marker compounds showed obvious diurnal/seasonal patterns. Surprisingly, due to the combined influence of weakened East Asian monsoons and land-sea breezes, all detected organic markers decreased except α/ß-pinene SOA markers during land-sea breeze periods in early autumn; whereas, all the organic markers increased except α/ß-pinene SOA markers, pollen and plant debris markers during land-sea breeze periods in early spring. Furthermore, the reaction pathway and aging of biogenic SOA were also related to land-sea breezes. During the land-sea breeze periods, the ratios of 2-methylglyceric acid (2-MGA) to 2-methyltetrols increased in early autumn, indicating that more isoprene-derived SOA generated from the high-NOx (nitrogen oxides) pathway when the land-sea breezes occurred; while the ratios decreased in early spring, this may be related to the chemical transformation of 2-MGA to 2-MGA sulfates. Changes in the ratio of monoterpene SOA markers demonstrate that monoterpene SOA was relatively aged during sea breeze periods, while it was fresher when the land breeze occurred. Although boundary layer height, emissions, gas/particle partitioning, etc. are important reasons for the diurnal variations of organic aerosols, night/day ratios of molecular markers increased obviously when land-sea breezes occurred in both early autumn and early spring. Our results provide new insights into the shift in the chemical composition of organic aerosols over coastal areas that are influenced by land-sea breezes.

Intimately tracking NO2 pollution over the New York City - Long Island Sound land-water continuum: An integration of shipboard, airborne, satellite observations, and models.

Nitrogen dioxide (NO2) pollution remains a serious global problem, particularly near highly populated urbanized coasts that face increasing challenges with climate change. Yet, the combined impact of urban emissions, pollution transport, and complex meteorology on the spatiotemporal dynamics of NO2 along heterogeneous urban coastlines remains poorly characterized. Here, we integrated measurements from different platforms - boats, ground-based networks, aircraft, and satellites - to characterize total column NO2 (TCNO2) dynamics across the land-water continuum in the New York metropolitan area, the most populous area in the United States that often experiences the highest national NO2 levels. Measurements were conducted during the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS), with a main goal to extend surface measurements beyond the coastline - where ground-based air-quality monitoring networks abruptly stop - and over the aquatic environment where peaks in air pollution often occur. Satellite TCNO2 from TROPOMI correlated strongly with Pandora surface measurements (r = 0.87, N = 100) both over land and water. Yet, TROPOMI overall underestimated TCNO2 (MPD = -12%) and missed peaks in NO2 pollution caused by rush hour emissions or pollution accumulation during sea breezes. Aircraft retrievals were in excellent agreement with Pandora (r = 0.95, MPD = -0.3%, N = 108). Stronger agreement was found between TROPOMI, aircraft, and Pandora over land, while over water satellite, and to a lesser extent aircraft, retrievals underestimated TCNO2 particularly in the highly dynamic New York Harbor environment. Combined with model simulations, our shipborne measurements uniquely captured rapid transitions and fine-scale features in NO2 behavior across the New York City - Long Island Sound land-water continuum, driven by the complex interplay of human activity, chemistry, and local scale meteorology. These novel datasets provide critical information for improving satellite retrievals, enhancing air quality models, and informing management decisions, with important implications for the health of diverse communities and vulnerable ecosystems along this complex urban coastline.

Overview of the Lake Michigan Ozone Study 2017.

The Lake Michigan Ozone Study 2017 (LMOS 2017) was a collaborative multiagency field study targeting ozone chemistry, meteorology, and air quality observations in the southern Lake Michigan area. The primary objective of LMOS 2017 was to provide measurements to improve air quality modeling of the complex meteorological and chemical environment in the region. LMOS 2017 science questions included spatiotemporal assessment of nitrogen oxides (NO x = NO + NO2) and volatile organic compounds (VOC) emission sources and their influence on ozone episodes; the role of lake breezes; contribution of new remote sensing tools such as GeoTASO, Pandora, and TEMPO to air quality management; and evaluation of photochemical grid models. The observing strategy included GeoTASO on board the NASA UC-12 aircraft capturing NO2 and formaldehyde columns, an in situ profiling aircraft, two ground-based coastal enhanced monitoring locations, continuous NO2 columns from coastal Pandora instruments, and an instrumented research vessel. Local photochemical ozone production was observed on 2 June, 9-12 June, and 14-16 June, providing insights on the processes relevant to state and federal air quality management. The LMOS 2017 aircraft mapped significant spatial and temporal variation of NO2 emissions as well as polluted layers with rapid ozone formation occurring in a shallow layer near the Lake Michigan surface. Meteorological characteristics of the lake breeze were observed in detail and measurements of ozone, NOx, nitric acid, hydrogen peroxide, VOC, oxygenated VOC (OVOC), and fine particulate matter (PM2.5) composition were conducted. This article summarizes the study design, directs readers to the campaign data repository, and presents a summary of findings.