While the impacts of cigarette smoking on human health are widely known, a less recognized impact of tobacco product use and disposal is environmental pollution. This review discusses the current literature related to cigarette and e-cigarette contamination in the context of environmental sources and impacts, with a focus on the documented influences on biota, ranging from bacteria to mammals. Cigarette butts and electronic cigarette components can leach contaminants into soil, water, and air. Cellulose acetate cigarette filters comprising the butts are minimally degradable and are a source of bulk plastic and microplastic pollution, especially in aquatic ecosystems where they tend to accumulate. Cigarette combustion and aerosol production during e-cigarette use result in air contamination from sidestream, exhaled, and thirdhand pathways. The chemical byproducts of tobacco product use contaminate wastewater effluents, landfill leachates, and urban storm drains. The widespread detection of nicotine and cotinine in the environment illustrates the potential for large-scale environmental impacts of tobacco product waste. Studies show that cigarette butt leachate and nicotine are toxic to microbes, plants, benthic organisms, bivalves, zooplankton, fish, and mammals; however, there remain critical knowledge gaps related to the environmental impacts of tobacco product waste on environmental health and ecosystem functioning.

Wireless sensor networks (WSNs) are a relatively new and rapidly developing technology; they have a wide range of applications including environmental monitoring, agriculture, and public health. Shared technology is a common usage model for technology adoption in developing countries. WSNs have great potential to be utilized as a shared resource due to their on-board processing and ad-hoc networking capabilities, however their deployment as a shared resource requires that the technical community first address several challenges. The main challenges include enabling sensor portability: (1) the frequent movement of sensors within and between deployments, and rapidly deployable systems; (2) systems that are quick and simple to deploy. We first discuss the feasibility of using sensor networks as a shared resource, and then describe our research in addressing the various technical challenges that arise in enabling such sensor portability and rapid deployment. We also outline our experiences in developing and deploying water quality monitoring wireless sensor networks in Bangladesh and California

Summary: Measuring CO₂ concentrations and fluxes is key to the evaluation of terrestrial ecosystem carbon dynamics. Both the high cost and low portability of currently available sensors and field instruments are constraints to achieving adequate spatial and temporal coverage in characterizing ecosystem CO₂ fluxes and point concentrations. We used commercially available, low‐cost and low‐power non‐dispersive infrared (NDIR) CO₂ sensors to develop: (i) a soil CO₂ efflux system (K‐33 ELG sensor, 0–1% or 10 000 ppm(v)) and (ii) a point CO₂ concentration system (K‐33 BLG sensor, 0 to 30% or 300 000 ppm(v)). We first calibrated the sensors against benchmark instruments (LI‐COR LI‐6400 efflux system and Vaisala GMP343 probe). The K‐33 ELG sensor tracked the LI‐6400 well during a steady reduction from ˜ 4000 ppm to background CO₂ levels (RMSE = 176 ppm). The K‐33 BLG point sensor were less favourable (RMSE = 424 ppm) because of its broad range of detection, but were suitable for proof‐of‐concept testing at elevated CO₂ levels (> 1500 ppm). In field tests of soil CO₂ efflux on locations with and without leaf litter, the K‐33 efflux system yielded mean surface efflux rate values significantly lower (by ˜ 27%) than those obtained with a LI‐COR LI‐6400 for the bare (P = 0·006) and litter (P = 0·002). We explain the systematic difference in terms of flux chamber geometry and potential leakage from the prototypical system. In a test on leaf cutter ant nest vents, the K‐33 BLG point system yielded comparable spatial and temporal patterns and slightly higher (˜ 10–15%) CO₂ concentrations in comparison with a Vaisala GMP343 probe. The results provide proof‐of‐concept for the use of two low‐cost, portable CO₂ sensing systems to enable terrestrial ecologists to substantially improve the characterization of CO₂ fluxes and concentrations in heterogeneous environments.

Leaf‐cutter ants are dominant herbivores that disturb the soil and create biogeochemical hot spots. We studied how leaf‐cutter ant Atta cephalotes impacts soil CO₂ dynamics in a wet Neotropical forest. We measured soil CO₂ concentration monthly over 2.5 years at multiple depths in nonnest and nest soils (some of which were abandoned during the study) and assessed CO₂ production. We also measured nest and nonnest soil efflux, nest vent efflux, and vent concentration. Nest soils exhibited lower CO₂ accumulation than nonnest soils for the same precipitation amounts. During wet periods, soil CO₂ concentrations increased across all depths, but were significantly less in nest than in nonnest soils. Differences were nonsignificant during drier periods. Surface efflux was equal across nest and nonnest plots (5 μmol CO₂ m⁻² s⁻¹), while vent efflux was substantially (10³ to 10⁵ times) greater, a finding attributed to free convection and sporadic forced convection. Vent CO₂ concentrations were less than in soil, suggesting CO₂ efflux from the soil matrix into the nest. Legacy effects in abandoned nests were still observable after more than two years. These findings indicate that leaf‐cutter ant nests provide alternative transport pathways to soil CO₂ that increase total emissions and decrease soil CO₂ concentrations, and have a lasting impact. Estimated total nest‐soil CO₂ emissions were 15 to 60% more than in nonnest soils, contributing 0.2 to 0.7% to ecosystem‐scale soil emissions. The observed CO₂ dynamics illuminate the significant carbon footprint of ecosystem engineer Atta cephalotes and have biogeochemical implications for rainforest ecosystems.